Air conditioning system



2 Sheets-Sheet 1 Feb. 25, 1 4 c. M. ASHLEY ETAL AIR CONDITIONING SYSTEM Filed May 5, 1960 F I6. I

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Feb. 25, 1964 c. M. ASHLEY ETAL AIR CONDITIONING SYSTEM 2 Sheets-Sheet 2 Filed May 5, 1960 INVENTOR. M. ASHLEY MILTON H. COLEMAN E L U R A c ATTORNEY.

United States Patent 3,122,291 an: QEJDZTISIWG SYSTEi l Carlyle M. Ashley, Fayetteville, and Milton H. ijolemm, East Syracuse, NBC, assignors to Carrier orporation, Syracuse, N1 a corporation of Delaware Filed May 5, 196%, Ser. No. 25,986 4- Ciaims. 16526) This invention relates to air conditioning systems and more particularly to an air conditioning system having a plurality of room units in which the capacity of each unit is varied by modulating the flow of recirculated room through the heat exchanger in each unit of such system.

in an induction type air conditioning system disclosed, for example, in Carrier Patent No. 2,363,294, granted November 21, 194-4, room units have been employed in which the volume of primary air has been held constant while the temperature of secondary air induced through the unit heat exchanger has been varied by increasing or reducing the volume of condition ng medium flowing through the heat exchanger. Generally speaking, such systems involve expensive conditioning medium piping costs. Too, the valves for metering the amount of conditioning medium delivered to each heat exchanger are costly. As much of the system must be fabricated in the field, extensive engineering services are often retgaired.

The primary object of this invention is to provide an improved induction type air conditioning system designed to obviate the disadvantages present in previous systems of this type.

An object of this invention is to provide an air conditioning system containing an improved induction unit.

Another object of this invention is to provide an air conditioning system containing an improved induction unit including means for automatically varying the heat exch nge capacity of each induction unit by regulating the qua ';y or" secondary air passing over the heat exchanger in each induction unit.

Still another object of this invention is to provide an air conditioning system containing an improved induction unit including a bellows damper arrangement and a control therefor responsive to p ary air pressure.

A still further object of this invention is to provide an air conditioning system containing an induction unit including means moving a damper to increase unit heat exchange capacity and means moving the damper to decrease unit heat exchange capacity in response to primary air pressure, the separate means including a control responsive to the temperature of the secondary air.

A further object is to provide a novel method of operation of an air conditioning system. Other objects of the invention 1' ill be readily perceived from the following description.

The present invention relates to an air conditioning system for treating a plurality of areas. The system cornnrises the combination of a central tation remote from said areas, means for supplying air to be conditioned to said central station, a plurality of induction units, at least one in each area to be conditioned, means for delivering a quantity of high static pressure conditioned air for ventilation from said central station to said units, means in each of the units for discharging the conditioned air w in said units at relatively high velocity, means for Suppl, g within the units other air from within the areas to be conditioned induced by the high velocity dicharge of conditioned air within the units, means for discharging the conditioned air and the induced air from each of the units into the area served thereby, a heat exchanger in each unit, means for supplying conditioning medium to the heat exchangers, a damper in each unit for regulatthe heat exchanger, means urging said damper in a first direction increasing the passage of induced air through the heat exchanger, means for actuating the damper in response to a predetermined control air pressure to decrease the quantity of air passing through the heat exchanger and increase the quantity of air bypassing the heat exchanger, and means responsive to the temerature of the induced air for controlling the actuating means.

This invention further relates to a method of operating an air conditioning system comprising the steps of supplying primary from a central station to induce secondary irom an area being conditioned to pass in heat exchange relation with a conditioning medium, discharging the mixture of primary air and secondary air in the area being conditioned, moving a damper to regulate the quantity of secondary air being passed in heat exchange relation with the conditioning medium, controlling the damper by imposing primary air pressure upon a bellows actuator for the damper, and varying the air pressure imposed on the bellows actuator in response to the temperature of the secondary air to vary the quantity of secondary air passing in heat exchange relation with the conditioning medium.

The attached drawings illustrate a preferred embodiment of the present invention, in which like numerals designate like elements in each or" the several views, and in which:

FEGURE 1 is a diagrammatic view of an air conditioning system of the present invention;

PEGURE 2 is a perspective view of an air conditioning unit or" he present invention with parts broken away and illustrating the control for the bellows damper arrangement;

FIGURE 3 is a fragmentary sectional view of the air conditioning unit illustrating the bellows damper arrangement; and

FEGURZE 4 is a diagrammatic view of a control arrangement for the bellows damper arrangement of the present invention.

Referring to FIGURE 1 of the attached drawings, there is shown an air conditioning system of the induction type embodying the present invention. The system includes a central station 2 including dampers 3 through which exterior air to be conditioned may pass into the central station, a filter 4, a precooling coil 5, a spray attachment 6, a cooling coil 7, a heating coil 8 and a fan Fan Q draws air tlnough the dampers into the central station where the air is treated and supplies this treated air as a source of primary air through a riser l9 and run-outs ll to room units 12 placed in the areas 13 being treated. The primary air is at relatively high static pressure, preferably in the range between 1.5 inches water gage and 5 inches water gage, and at relatively high velocity, on the order of 3,900 to 5,096 feet per minute. it will be observed that room units 12 are shown diagrammaticaily, such units being illustrated in greater detail in FiG-URE 2.

A refrigeration machine 15 is provided to furnish cold water to the room units. Pump P draws cold water from the refrigeration machine and forwards the cold water through line to heat exchangers 32 in the room units 12, the water returning from the room units after passage in heat exchange relation with secondary air induced into the units through line 17 to the refrigeration machine.

A source of hot water 18 is also provided for passage to the heat exchangers of the room units during winter operating conditions. The hot water source 18 is connected to pump P by line 19 and to return line 17 by line 2%. Suitable valves V are provided in these lines to permit cold water or hot water to be furnished alternately to the room units as desired.

Referring to FIGURE 2, there is shown a perspective view of a room unit 12. Room unit L. includes a removable enclosure 24. Within the enclosure is a base unit in which is placed a plenum chamber as connected to runout 11 by duct portion 27 to permit primary air to be supplied tothe plenum chamber. Plenum chamber 26 is provided with suitable discharge means 28 to discharge primary air within the u Discharge means 28 may consist of separate spaced nozzles, as shown, or may be a single slot-type nozzle. The how of air from plenum chamber 26 to nozzles 23 through the slot 2% may be regulated to maintain a predetermined pressure at the nozzles by means of slide plate or balancing damper 39 w. ich is movable to open and close slot 29. Suitable adjustment means 31 as, for example, a screw movable through the base unit 25 is provided to adjust the slide plate 3%.

It will be understood, of course, the base unit described may be provided with an enclosure or casing, as shown, or furred in the building or structure, as desired.

A heat exchanger 32 is placed in base unit 25 and is adaptedto be connected to lines it: and 17 to permit conditioning medium to be passed therethrough. Heat exchanger 32 is spaced from plenum chamber 26 and provides a bypass passage 33 for secondary air. Wall 3 of base unit 25 prevents passage of secondary through heat exchanger 32 when the bypass passage is fully opened. The room unit may be suspended from the wall 35 of the building structure. Preferably, the room unit is spaced from the floor 35 of the building structure to permit secondary room air to be induced into the unit from the bottom thereof.

Removable enclosure 24 of unit 12 includes an inlet 37 in the bottom thereof to permit secondary air to be induced into the unit and an outlet 38 in the top thereof to permit a mixture of primary air and secondary air to be discharged into the area being treated.

Passage of secondary air through heat exchanger 52 of the unit is regulated by means of a bellows damper arrangement 39. Arrangement 39 includes a damper 49 substantially coextensive with the length of heat exchanger 32. Damper ll is connected to shaft ll which is iournalled in supports 41' secured to base unit 25. Shaft is urged by counterbalance 43 in a direction to permit the damper to close bypass passage and thus direct all induced air through the heat exchanger.

The means for actuating damper dill to open the bypass passage comprises an expansible member or bellows made of elastomeric coated fabric, preferably nylon coated with neoprene. Two reinforcing strips 45 are suitably bonded to the inside of the bellows to provide support therefor. The top of bellows 44 is reinforced along its lateral length by a pair of stiifening strips 1'5. The strips 45, 56 may be formed from metal, as for example, aluminum or from plastic, as for example, polyester Preferably the bellows fabric does not expand and contract but rather the side walls of the bellows pivot with respect to one another about hinge means formed by the apex of the bellows connecting the side walls in response to variation in pressure within the bellows. One side of bellows 44 is affixed to a suitable support bracket 43 which is fixedly mounted with respect to base unit 25. The other side wall of the bellows pivots in response to an increase of pressure within the bellows and has affixed to it a ii-shaped protector plate 49. The portion s? of the protector plate bears against button 5%, preferably made from plastiqon the damper 49 to actuate the latter. The portion 4% of the protector plate prevents dirt from accumulating in the upper portion of the bellows and interfering with the operation thereof. Connector 4-7 is adapted to communicate bellows 44 with a source of control air.

In FIGURE. 4 there is shown a suitable control arrangement for the bellows damper arrangement 39. Referring to FIGURE 4, there is shown a line 51 in communication with the plenum chamber 26. The small quantity of air directed from the plenum chamber above the slide is fed through air filter 52 to eliminate the ticles which may have escaped the primary air system. The air then passes through line 53 to the air PIESSE1 regulator as which will maintain a constant downstream pressure of approximately 1.5 inches of water column. Air then passes through line 55 to a triction T Within the restriction T is a sharp-edged ce 5'7 from which the air passes into lines 59 and 61 Line 59 is connected to restriction T as approximately at he vena contracta or" orifice 57, As a consequence lower pressures result within bellows 44-, which enables counterbalance 43 to more easily move damper til to close bypass passage 33. A safety relief valve 53 is provided in the restriction T 56. Line 5* connects one port of restriction T 56 with the bellows 4d and line 66 connects the restriction T with the changeover valve 61. The changeover valve communicates line 64 with either line 66 or 67 dependent upon the temperature of the fluid in heat exchanger Preferably, changeover valve 6?, is regulated by 1 cans of a thermal actuator 52 placed on heat exchanger 32 so that it is responsive to the temperature of conditioning medium passing through the heat exchanger. ce warm water is supplied to the heat exchanger under winter operating conditions and coldwater is supplied to the heat exchanger under summer operating conditions it will be appreciated that valve 61 selects the line in use under these various operating conditions.

Control 6?: which is responsive to the temperature in the area being treated is connectedto the lines as and 57 r spectively. Control 68 includes casing 69 having inlet 7% in communication with. the secondary air by means of duct Tl and an outlet '72 in communication with the assage adjacent the nozzles 28. The control also includes l bimetallic elements 7 3 and 74 adiacent the outlets of each line 66 and er. Birnetmlic elements 73 and 74 sense the temperature of the secondary air induced through the casing 6) to bleed air from lines 6-5 andi, respectively, thus varying the pressure imposed in bellows 4 during the various operating conditions.

Considering the operation of the air conditioning system under summer conditions, primary air is supplied from central station 2 through riser 1% to the plenum chamber 26 in each unit 12. The primary air is discharged through nozzles 28 inducing secondary air from the areas 13 through inlet 37 into each unit 12. Counterbalance 43 urges damper 4t clockwise as viewed in FEGURE 4 to close bypass passage 33 so that all the secondary air induced into the unit passes through heat exchanger 32. Primary control air flows from plenum chamber 26 through line 53, filter 52, pressure regulator 54, and restriction T as through line 5% to the expansible member or bellows 44. The thermal actuator 62 of change' over valve 61 senses the temperature of the cooling medium and moves valvel to place line as in communication with line 67. The outlet from line 67 is open permitting air to bleed to the atmosphere. Bellows 44, therefore, has insufiicient control pressure therein and the damper 4t) remains under control of counterbalance 4-3. Room air passes over heat exchanger 32 and is cooled thereby. Assuming, however, that the temperature in the area being treated decreases to the desired temperature, the decrease in temperature is sensed by bimetallic element '73 which warps to close the outlet from line 6'7. The pressure rise in the line 67 will be felt bacl: through the interconnecting tubing to expansible member 44 where expansion will take place and damper 413 will be moved toward opening the bypass passage thereby reducing ilow of secondary air through heat enchanger 32. When bimetallic element 73 opens in response to a demand for cooling, the opposite reaction will take place and damper 49 will move to close bypass pas sage 33 thereby increasing flow of air over heat exchanger 32 and reducing the amount of the bypass air stream.

Similarly, under wiriter operating conditions, change over valve 61 is actuated to place line 63 in communication with line 66 in response to the temperature of the heating medium passing through heat exchanger 32. Damper 49 is urged clockwise, as seen in FIGURE 4, by counterbalance 43 to close bypass passage 33 and increase the heating of secondary air. Primary control air flows through line 51, filter 52, pressure regulator 54, restriction orifice 57 in restriction T 56 to the bellows 44 through line 59. As bimetallic element 74 is warped in response to a demand for more heating, line 66 is opened to the atmosphere and damper 40 remains under the control of the counterbalance 43. When bimetallic element 74 warps and closes the outlet from line 66 in response to the increased temperature of the secondary air passing over the bimetallic element, the pressure will increase in the system. Damper 40 will move toward closing the passage of air through heat exchange coil 32 and at the same time increasing the passage of air bypassing the heat exchanger 32. When the temperature sensed by the bimetallic element 74 decreases the opposite action will take place. Bimetallic element 74 will open the outlet from line 66 permitting primary control air to bleed to the atmosphere thereby relieving the pressure within the expansible member and permitting the damper to close the bypass passage permitting more secondary air to pass over heat exchanger 32 and increasing the capacity of the unit. Thus it is seen that the thermostat is a modulating device both in summer and in winter.

The control 68 is adapted for use in a nonchangeover system. If, for example, the control is employed in a system designed only for cooling, then a connection is made from the restriction T directly to the cooling port of the control, eliminating changeover valve 61.

The present invention provides an air conditioning system wherein the flow of primary air and the fiow of conditioning medium to each unit in such system is constant. The air conditioning unit of the present invention includes an improved conditioning unit of economical design which contains eflicient automatic means for varying the heat exchange capacity of each unit by regulating the quantity of secondary air passing over the heat exchanger. The automatic control means rnay be integrated within a modular unit used in the system of the present invention. The air conditioning system of the present invention contains a plurality of air conditioning units each of which may be almost wholly constructed in a factory thus eliminating the need for and the cost of engineering services in the field. The use of the air conditioning system of the present invention greatly simplifies and reduces the cost of the water piping associated with such system.

While we have described a preferred embodiment of the present invention, it will be understood the invention is not so limited since it may be otherwise embodied within the scope of the following claims.

We claim:

1. In an air conditioning unit, the combination of a casing, a plenum chamber in said casing adapted to be placed in communication with a source of supply air, said plenum chamber having discharge means therein to discharge primary air within the casing, a heat exchanger in said casing adapted to be placed in communication with a source of heat exchange medium, said casing having an inlet and an outlet therein, discharge of primary air in the unit inducing secondary air from the area being conditioned through the inlet into the unit to mix with primary air, the mixture being discharged through the outlet, a damper for regulating the quantity of secondary air passing through or bypassing the heat exchanger, said damper being pivotally mounted within said casing, teams for moving said damper in a first direction, and a control for moving said damper in a second direction comprising an expansible member for actuating said damper, means for communicating the expansible member with the plenum chamber, and means for controlling the pressure within the expansible member in response to the temperature of secondary air.

2. In an air conditioning unit, the combination of a casing, a plenum chamber in said casing adapted to be placed in communication with a source of primary air, said plenum chamber having discharge means therein to discharge primary air Within the casing, a heat exchanger in said casing adapted to be placed in communication with a source of heat exchange medium, said casing having an inlet and an outlet therein, discharge of primary air in the casing inducing secondary air from the area being conditioned through the inlet into the casing to mix with primary air, the mixture being discharged through the outlet, a damper to regulate the quantity of secondary air passing through or bypassing the heat exchanger, an expansible member operatively connected to said damper to actuate the same, and means for controlling the operation of said expansible member responsive to primary air pressure, said controlling means comprising means for bleeding air to the atmosphere in response to the temperature of the induced secondary air, said damper being biased toward a first position to pass substantially all the secondary air through the heat exchanger and said expansible member urging said damper toward a second position to bypass substantially all the secondary air about said heat exchanger.

3. An air conditioning unit as in claim 2 wherein said heat exchanger is adapted to be supplied selectively with either a hot or a cold heat exchange medium and said controlling means include a changeover valve communicating with a first line open to the atmosphere when the heat exchanger is cooling secondary air and communicating with a second line open to the atmosphere when the heat exchanger is heating secondary air, and a control for closing said first line and said second line, respectively, to the atmosphere in response to a first predetermined temperature and a second predetermined temperature of the secondary air to expand the expansible member and actuate the damper.

4. In a method of operating an air conditioning unit the steps which consist in supplying primary air to induce secondary air from an area being conditioned to pass in heat exchange relation with a conditioning medium, discharging the mixture of primary air and secondary air into the area being conditioned, actuating a control in response to pressure derived from the primary air to decrease the quantity of secondary air being passed in heat exchange relation with the conditioning medium, and selectively communicating the control with the atmosphere in response to the temperature of the induced air to permit an increase in the quantity of secondary air being passed in heat exchange relationship with the conditioning medium.

References Cited in the file of this patent UNITED STATES PATENTS 1,904,918 Ewald Apr. 18, 1933 2,567,758 Ashley Sept. 11, 1951 2,705,595 Carlson et al May 5, 1955 2,906,287 Kreuttner Sept. 29, 1959 2,913,227 Bottorf et al Nov. 17, 1959 2,957,629 Curran Oct. 25, 1960 

1. IN AN AIR CONDITIONING UNIT, THE COMBINATION OF A CASING, A PLENUM CHAMBER IN SAID CASING ADAPTED TO BE PLACED IN COMMUNICATION WITH A SOURCE OF SUPPLY AIR, SAID PLENUM CHAMBER HAVING DISCHARGE MEANS THEREIN TO DISCHARGE PRIMARY AIR WITHIN THE CASING, A HEAT EXCHANGER IN SAID CASING ADAPTED TO BE PLACED IN COMMUNICATION WITH A SOURCE OF HEAT EXCHANGE MEDIUM, SAID CASING HAVING AN INLET AND AN OUTLET THEREIN, DISCHARGE OF PRIMARY AIR IN THE UNIT INDUCING SECONDARY AIR FROM THE AREA BEING CONDITIONED THROUGH THE INLET INTO THE UNIT TO MIX WITH PRIMARY AIR, THE MIXTURE BEING DISCHARGED THROUGH THE OUTLET, A DAMPER FOR REGULATING THE QUANTITY OF SECONDARY AIR PASSING THROUGH OR BYPASSING THE HEAT EXCHANGER, SAID DAMPER BEING PIVOTALLY MOUNTED WITHIN SAID CASING, MEANS FOR MOVING SAID DAMPER IN A FIRST DIRECTION, AND A CONTROL FOR MOVING SAID DAMPER IN A SECOND DIRECTION COMPRISING 